Heat treating and temering 1084

S

Skyfntm

Joined
Jul 30, 2012
Messages
16
Hey guys,

I have recently ordered some 1084 from Aldo and I'm waiting for it to arive.

I have been researching all that I need for making my first (known metal) knife. What I have not been able to find is how to heat treat and temper the metal. What I have found is that I am to quench in canola oil pre heated to 130 F. But what I dont know is how to get it to that point. I plan on doing everything myself (cutting, shaping, micarta scales, kydex sheath, HT).

The way that I plan on heating the metal is on a coal forge (since I can't afford a HT oven). What color does the metal need to be and for how long? Also after I get it to that point do I drop it strait into the quench or do i gradualy introduce the metal to the quench? Do I need to perform this multiple times or is one time enough?

Also on the tempering I have read that I can do this in my oven at the house. Is this correct? If so how do I perform this task to acheive the proper temper on the metal?

Any and all information regarding this subject will help me emencly.

Thanks for taking the time to read this and respon.

Skyler
 
AVigil, I've been looking for easy HT info on 1084 also. I did find that article by Kevin, but that is for people with a HT oven. What if the only thing we have is a torch?
 
A torch isn't really a good way to HT, but it will work for 1084.

Here is a basic HT regimen forn 1084:
1084 HT:
refine grain and normalize -
heat to 1500F and air cool to black, then quench to cool
heat to 1350F ( just non-magnetic) and air cool to black, then quench to cool
heat to 1200F ( still magnetic) and air cool to black, quench to cool
Straighten any warp or twist

Austenitize-
heat to 1500F and hold long enough to allow the blade to be evenly heated
quench in a fast quenchant (or as fast as you have, canola will work for all but big blades)
Check for warp after holding in the quench oil for 5-8 seconds. Straighten immediately. Stop after about 20-30 seconds, as the blade will be too cool and may break.

Temper immediately at 450F for two hours, twice. Quench in water to cool between temper cycles.
( If there is any warp after the blade cools, it can usually be straightened while at tempering temperature. Let it heat for 30 minutes before any straightening.)
 
bladsmth said:
A torch isn't really a good way to HT, but it will work for 1084.

Here is a basic HT regimen forn 1084:
1084 HT:
refine grain and normalize -
heat to 1500F and air cool to black, then quench to cool
heat to 1350F ( just non-magnetic) and air cool to black, then quench to cool
heat to 1200F ( still magnetic) and air cool to black, quench to cool
Straighten any warp or twist

Austenitize-
heat to 1500F and hold long enough to allow the blade to be evenly heated
quench in a fast quenchant (or as fast as you have, canola will work for all but big blades)
Check for warp after holding in the quench oil for 5-8 seconds. Straighten immediately. Stop after about 20-30 seconds, as the blade will be too cool and may break.

Temper immediately at 450F for two hours, twice. Quench in water to cool between temper cycles.
( If there is any warp after the blade cools, it can usually be straightened while at tempering temperature. Let it heat for 30 minutes before any straightening.)
Click to expand...

Thanks Stacy,

that is closer to what I'm looking for. But I dont have a way to tell the temperature. I will try and find a color chart that coincides with the temperatures that you have stated. That way I can post it for guys like me that dont have a way to get the temp or have a HT oven that is temp controlled.

Edit: I have found a color chart that will help us EyeBallers to guesstimate the temperature of the blade. I'm not sure on posting pics so I will give the sight address. http://www.simplytoolsteel.com/temperature-color-guide.html
 
Last edited:
Color charts are okay. People see colors slightly different. Your blade goes non-magnetic at 1414 degrees. I have a PID to monitor my temps, but, I also have a magnet on the side of my forge stand. You can put a knife in the forge, or if using a torch, heat it until the blade will not stick to to the magnet. Then take the steel around one shade lighter before quenching. That's the best way to tell without a PID.
Never rely entirely on color as the ambient light will also effect whet the steel looks like when it's 1475-1500 degrees.
 
What Brian said! I do my HT'ing at night so I can see that the blade is evenly heated. Ambient light makes a huge difference on perceived colour.
Use the magnet method.
 
Brian Ayres said:
Color charts are okay. People see colors slightly different. Your blade goes non-magnetic at 1414 degrees. I have a PID to monitor my temps, but, I also have a magnet on the side of my forge stand. You can put a knife in the forge, or if using a torch, heat it until the blade will not stick to to the magnet. Then take the steel around one shade lighter before quenching. That's the best way to tell without a PID.
Never rely entirely on color as the ambient light will also effect whet the steel looks like when it's 1475-1500 degrees.
Click to expand...

SBranson said:
What Brian said! I do my HT'ing at night so I can see that the blade is evenly heated. Ambient light makes a huge difference on perceived colour.
Use the magnet method.
Click to expand...

Thanks guys. I had planned on doing all my HT at night also, for the same reason that SBranson said. As for the magnet, do I need a really strong magnet? Or does it really mater?
 
You can get an 900*C (1652*F) Infrared thermometer on ebay for around $50. You can buy a garden torch from harbor freight for around $30.

That will provide you with heat and a way to monitor it. If you watch Carl Andersens series on YouTube you can see him use the IR thermometer.

It works very well and you can easily determine when a metal reaches the Currie point and take the temp to see where it is at. Mine is spot on. You can also adjust it for the type of surface it will read off of and it will self adjust. You can also program it for the temp you need and it will signal when it goes over temp or under temp. Very handy while heat treating. Remember it is the temperature of the metal that is important not the temp of the sensor in the oven. You can read the temp of an entire blade in seconds.

They also sell some that can read over 2000* but they cost about $80 These are not the cheap Harbor Freight models. I have one of those and it pales in comparison to the one I got off of Ebay.

The pict below shows one that reads up to 2102 F* and it is $68 on Ebay right now. I can not post link because the would be deal spotting sorry


18473.jpg
 
Last edited:
Those low price non-contact IR thermometers are very poor at reading temps above 900F ( HF sells a 900F unit, but I thought they stopped selling the 1600F unit). They are fine for checking the temper range, or checking the quench oil, but almost useless for testing red hot steel. Once the steel starts to glow, you are lucky to be 5-10% off in the bright red range.
I have a $1K+ lab unit that I still would not use to read a blade temp for HT. Emissivity, reading angle, and other factors can skew the reading far too much for HT accuracy. At 1500F, 5% error is 75°...... so you could be anywhere from 1425 to 1575 ????? (Both will read non-magnetic, BTW)

As to reading the colors by eye. This has been tested many times....and found to be one of the poorest ways.
Most old timers will state that they have enough experience to tell the temp of hot steel....because they have seen so much of it they have learned. This was tested ( IIRC, by the AABANA) at a blacksmiths seminar where steel was heated in controlled ovens and the smiths were asked to write down the temperature they thought it was by judging the color only. They were randomly shown steel pieces at 1400, 1600, 1800, and 2000F. The range of error was huge, from 30% low to 20% high. Only a small number of guesses were close, and those people were inconsistent for the whole range. The smiths averaged being over 200F too low for the whole study. As a group, they thought 1600F steel was around 1400F. That could really mess up a HT.
The lighting conditions when viewing hot steel can also make the color look very different.

A magnet won't tell you 1500F, but it will tell you when the steel crosses 1414F. A little longer and a little brighter red and you are good enough for 1084.

I don't know a smith who does not have a magnet on/by his forge.

All that said, a refractory forge that has been fully pre-heated........ with some sort of control over the heat ( a needle valve at the minimum) ..........and a PID with a 10 gauge type K TC will give you consistent and fairly accurate readings. The PID, TC and any needed hookup items can be purchased for less than $100. Sometimes near half that.
 
Last edited:
bladsmth said:
Those low price non-contact IR thermometers are very poor at reading temps above 900F ( HF sells a 900F unit, but I thought they stopped selling the 1600F unit). They are fine for checking the temper range, or checking the quench oil, but almost useless for testing red hot steel. Once the steel starts to glow, you are lucky to be 5-10% off in the bright red range.
I have a $1K+ lab unit that I still would not use to read a blade temp for HT. Emissivity, reading angle, and other factors can skew the reading far too much for HT accuracy. At 1500F, 5% error is 75°...... so you could be anywhere from 1425 to 1575 ????? (Both will read non-magnetic, BTW)

As to reading the colors by eye. This has been tested many times....and found to be one of the poorest ways.
Most old timers will state that they have enough experience to tell the temp of hot steel....because they have seen so much of it they have learned. This was tested ( IIRC, by the AABANA) at a blacksmiths seminar where steel was heated in controlled ovens and the smiths were asked to write down the temperature they thought it was by judging the color only. They were randomly shown steel pieces at 1400, 1600, 1800, and 2000F. The range of error was huge, from 30% low to 20% high. Only a small number of guesses were close, and those people were inconsistent for the whole range. The smiths averaged being over 200F too low for the whole study. Ads a group, they thought 1600F steel was around 1400F. That could really mess up a HT.
The lighting conditions when viewing hot steel can also make the color look very different.

A magnet won't tell you 1500F, but it will tell you when the steel crosses 1414F. A little longer and a little brighter red and you are good enough for 1084.

I don't know a smith who does not have a magnet on/by his forge.

All that said, a refractory forge that has been fully pre-heated........ with some sort of control over the heat ( a needle valve at the minimum) ..........and a PID with a 10 gauge type K TC will give you consistent and fairly accurate readings. The PID, TC and any needed hookup items can be purchased for less than $100. Sometimes near half that.
Click to expand...

Well I guess I will have to wait to get my blades HT'd till I cant get a refractory forge made. Thanks again guys for all the help.
 
Skyfntm said:
Well I guess I will have to wait to get my blades HT'd till I cant get a refractory forge made. Thanks again guys for all the help.
Click to expand...
You don't have to wait as long as your expectations don't exceed your means. You can heat treat a knife in a campfire, if it is all you have. I feel that in the beginning, it is more important to start making knives anyway you can, than to not make any at all. This is a fun craft. BUT you have to be honest with yourself at the same time. Don't play off proper methods as unnecessary or overkill..... there is a RIGHT WAY to make knives for a given purpose and that should be the ultimate goal. EVOLVE into a skilled knifemaker but do what you can in the present.

Personally, I think starting low-tech is a great way to build a solid foundation. You obviously will never make a silk purse from a sow's ear but you can sure try to get close. Just think of how far ahead you'll be once you get that ream of silk!

Knifemaking is a "con" game..... confidence, consistency, continuous improvement.
 
Last edited:
sorry to jack thread but where is the best place to put the tc? right against the blade? and does aldo's 1084 need to be normalized following that sequence? I thought it was annealed already.
 
Aldo recommends normalizing his 1084FG. The t/c should be in the vacinity of the blade. Some folks use more than one t/c but Stacy would be more of an authority than I.
 
I second what Sbranson said about doing HT at night. I started getting much more consistent and better results when I started doing this. And get a magnet, but be careful you don't hold it on the hot steel too long or it will lose its magnetism. If you use one of those telescopic pickup magnets like I use, the glue that holds the magnet in the socket can melt — just tap the magnet on the blade to see if it will stick.

- Chris
 
Rick Marchand said:
I feel that in the beginning, it is more important to start making knives anyway you can, than to not make any at all. This is a fun craft. BUT you have to be honest with yourself at the same time. Don't play off proper methods as unnecessary or overkill..... there is a RIGHT WAY to make knives for a given purpose and that should be the ultimate goal. EVOLVE into a skilled knifemaker but do what you can in the present.

Personally, I think starting low-tech is a great way to build a solid foundation. You obviously will never make a silk purse from a sow's ear but you can sure try to get close. Just think of how far ahead you'll be once you get that ream of silk!

Knifemaking is a "con" game..... confidence, consistency, continuous improvement.
Click to expand...

Rick, very well put. Some great information here as elsewhere on the forums, but seldom have I had someone put their (and my own) approach to knifemaking so well.
Thank you
Willem
 
Hesparus...

I ran into the same problems. My solution was to eliminate direct contact with the piece and not have to rely on an adhesive to hold the magnet in place. I hammered out the end of a length of 1/4" mild roundstock and stuck one of those strong button magnets on it. The end is turned up and I use the backside of the flattened rod to touch the hot steel.

IMG_0186-1.jpg
 
Rick Marchand said:
You don't have to wait as long as your expectations don't exceed your means. You can heat treat a knife in a campfire, if it is all you have. I feel that in the beginning, it is more important to start making knives anyway you can, than to not make any at all. This is a fun craft. BUT you have to be honest with yourself at the same time. Don't play off proper methods as unnecessary or overkill..... there is a RIGHT WAY to make knives for a given purpose and that should be the ultimate goal. EVOLVE into a skilled knifemaker but do what you can in the present.

Personally, I think starting low-tech is a great way to build a solid foundation. You obviously will never make a silk purse from a sow's ear but you can sure try to get close. Just think of how far ahead you'll be once you get that ream of silk!

Knifemaking is a "con" game..... confidence, consistency, continuous improvement.
Click to expand...

You are right. I'm just getting into this and I dont have that high of expectation for my blades... YET. I know there is going to be some trial and error in the quest to refine my skills.

I will go forth with the forge HT at night and see what I get. As soon as I get my 1084 from Aldo I will start the first knife. HT and all. put it through the ringer and go from there.
 
Skyfntm said:
You are right. I'm just getting into this and I dont have that high of expectation for my blades... YET. I know there is going to be some trial and error in the quest to refine my skills.

I will go forth with the forge HT at night and see what I get. As soon as I get my 1084 from Aldo I will start the first knife. HT and all. put it through the ringer and go from there.
Click to expand...

Cool... have fun.

My only fear is that some new makers hear about crazy mystical heat treat rituals, make a knife, test it a bit, think they've found the secret formula and spread the word like wildfire. It could be just dumb luck or improper testing but "Doing the holky-polky while quenching in rendered bear fat with the tip pointing to magnetic North makes for great knives!":p

I would much rather have someone post a knife and say... "I simply heated it to non-magnetic, gave it an addotional 7-count and plunged it into canola. It worked out well and I'm happy with the performance." THAT is honesty, without hype.
 
You must log in or register to reply here.
Back
Top